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Working memory, the ability to keep recently accessed information available for immediate manipulation, has been proposed to rely on two mechanisms that appear difficult to reconcile: self-sustained neural firing, or the opposite—activity-silent synaptic traces. Here we review and contrast models of these two mechanisms, and then show that both phenomena can co-exist within a unified system in which neurons hold information in both activity and synapses. Rapid plasticity in flexibly-coding neurons allows features to be bound together into objects, with an important emergent property being the focus of attention. One memory item is held by persistent activity in an attended or “focused” state, and is thus remembered better than other items. Other, previously attended items can remain in memory but in the background, encoded in activity-silent synaptic traces. This dual functional architecture provides a unified common mechanism accounting for a diversity of perplexing attention and memory effects that have been hitherto difficult to explain in a single theoretical framework.

Resource constrained devices such as sensors and RFIDs are utilized in many application areas to sense, store and transmit the sensitive data. This data must be encrypted to achieve confidentiality. The implementation of traditional public key encryption (PKE) techniques by these devices is always challenging as they possess very limited computational resources. Various encryption schemes based on identity-based encryption (IBE) and certificate-less public key encryption (CL-PKE) have been proposed to overcome limitations of PKI. However, many of these schemes involve the computationally expensive exponentiation and bilinear pairing operations on elliptic curve group to encrypt the messages. In this context, we propose a lightweight optimized CL-PKE scheme in which exponentiation and pairing operations are completely eliminated during encryption and only involves computation of cheaper addition and multiplication operations on elliptic curve. Implementation of the proposed scheme confirms its lightweight nature as compared to original CL-PKE scheme.

For many Intelligent Transportation System (ITS) applications, periodic transmission of beacon messages by a source vehicle is paramount for providing the unhindered service and to maintain its accuracy. A malicious source vehicle could deny beacon messages of a target ITS application and intelligently cover-up this denial with signal loss faced due to wireless channel error and surrounding environment obstacles. In this context, we propose a lightweight technique to detect a beacon denial attacker using Auto-Correlation Function (ACF). This technique possesses higher detection accuracy in comparison to fixed threshold scheme which depends upon the number of beacon messages denied by the source vehicle. Furthermore, we propose a random vehicle inspection scheme for inspecting randomly chosen set of vehicles for beacon denial attack. In addition to reducing computational overhead, the advantage of this scheme is that an attacker with knowledge about detection algorithm cannot decide the time and place of inspection. Simulation results confirm the accurate and lightweight nature of the proposed technique.

Visuospatial working memory allows us to hold multiple visual objects over short delays. It is typically tested by presenting an array of objects, then after a delay showing a ‘probe’ indicating which memory item to recall or reproduce by adjusting a target feature. However, recent studies demonstrate that information at the time of probe can disrupt recall. Here, in three experiments we test whether traditional memory probes, which contain features that compete with the feature to be recalled, may themselves interfere with performance. We asked participants to report the direction of one of the several coloured arrows in memory, based on its colour. First, we demonstrate that recall is better when the probe is initially just a coloured dot, rather than a coloured arrow which has to be adjusted to match orientation memory, consistent with interference from features of the probe itself. Second, this interference is present even when a mask follows the memory array, suggesting that the interference does not work by degrading immediate or iconic memory. Finally, when items are shown sequentially, the first and last items are invulnerable to probe interference. Our findings support recent theories of associative recall, in which probes reactivate features in WM, retrieving information by pattern completion.

Scardovia wiggsiae has recently been identified as a potential pathogen associated with dental caries. The aim of the present study was to detect and quantify S. wiggsiae from dental plaque samples of children suffering from severe early childhood caries and children who were caries free by employing a real time DNA polymerase chain reaction (Real-time PCR) method. Dental plaque samples were collected from children suffering from severe early childhood caries (S-ECC) (n = 30) and caries free children (CF) (n = 30) reporting to the out-patient clinics of the department of paediatric and preventive dentistry. Plaque samples from each group were subjected to real-time PCR, post DNA extraction. Both the groups showed the presence of the organism S. wiggsiae, however there was a significant difference in its quantification between groups, with the median number being 1.49 × 108 cells per ml in caries free samples compared to 1.40 × 109 cells per ml in S-ECC samples. S. wiggsiae were isolated from nearly all samples of children, both caries free and those suffering from S-ECC. However, their numbers differ drastically in both groups with the scales tipping towards the S-ECC group, proving their association with the disease process in a significant manner. The present study shows significant association of S. wiggsiae in severe early childhood caries.

Apathy is a syndrome of reduced motivation that commonly occurs in patients with cerebral small vessel disease, including those with the early onset form, CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy). The cognitive mechanisms underlying apathy are poorly understood and treatment options are limited. We hypothesized that disrupted effort-based decision-making, the cognitive process by which potential rewards and the effort cost required to obtain them is integrated to drive behaviour, might underlie the apathetic syndrome. Nineteen patients with a genetic diagnosis of CADASIL, as a model of ‘pure’ vascular cognitive impairment, and 19 matched controls were assessed using two different behavioural paradigms and MRI. On a decision-making task, participants decided whether to accept or reject sequential offers of monetary reward in return for exerting physical effort via handheld dynamometers. Six levels of reward and six levels of effort were manipulated independently so offers spanned the full range of possible combinations. Choice, decision time and force metrics were recorded. Each participant’s effort and reward sensitivity was estimated using a computational model of choice. On a separate eye movement paradigm, physiological reward sensitivity was indexed by measuring pupillary dilatation to increasing monetary incentives. This metric was related to apathy status and compared to the behavioural metric of reward sensitivity on the decisionmaking task. Finally, high quality diffusion imaging and tract-based spatial statistics were used to determine whether tracts linking brain regions implicated in effort-based decision-making were disrupted in apathetic patients. Overall, apathetic patients with CADASIL rejected significantly more offers on the decision-making task, due to reduced reward sensitivity rather than effort hypersensitivity. Apathy was also associated with blunted pupillary responses to incentives. Furthermore, these independent behavioural and physiological markers of reward sensitivity were significantly correlated. Non-apathetic patients with CADASIL did not differ from controls on either task, whilst actual motor performance of apathetic patients in both tasks was also normal. Apathy was specifically associated with reduced fractional anisotropy within tracts connecting regions previously associated with effort-based decision-making. These findings demonstrate behavioural, physiological and anatomical evidence that dysfunctional effort-based decision-making underlies apathy in patients with CADASIL, a model disorder for sporadic small vessel disease. Reduced incentivization by rewards rather than hypersensitivity to effort costs drives this altered pattern of behaviour. The study provides empirical evidence of a cognitive mechanism for apathy in cerebral small vessel disease, and identifies a promising therapeutic target for interventions to improve this debilitating condition.

Background: Recent investigations have shown the possible involvement of bacteria other than mutans group and Lactobacilli in the etiology of caries. Molecular methods have been used to study the microbial diversity in caries-active (CA) and caries-free (CF) children. Among them, denaturing gradient gel electrophoresis (DGGE) is more popular and has been used in the present study. Aims: The aim of the present study was to investigate the difference in bacterial diversity in saliva and plaque samples from CF and CA children using DGGE. Materials and Methods: The study involved saliva and plaque samples from 56 children of which 28 were CF, 20 with CA, and 8 with white spot lesions (WSP). DNA was extracted and subjected to polymerase chain reaction amplification with universal primers. It was then run in polyacrylamide gel electrophoresis with gradients of urea and formamide and stained with SYBR green. Multiple bands were produced in each sample lane and each band represents one organism. Statistical Analysis: A dendrogram was generated using Phoretix software and similarity index was calculated using a specific formula. Results: Samples in each group formed several clusters indicating a specific pattern of the bacterial profile. Similarity coefficient was calculated based on the number of bands, intensity, and location. The diversity was less in the saliva and plaque samples of CA group as compared to those of CF and WSP groups. Conclusions: DGGE can be used to study distinctive bacterial profiles in healthy and caries-affected sites. DGGE can be further developed as a pattern recognition tool with which to identify specific groups of bacteria. Saliva may be used to study bacterial diversity in dental caries.

Saccadic peak velocity increases in a stereotyped manner with the amplitude of eye movements. This relationship, known as the main sequence, has classically been considered to be fixed, although several recent studies have demonstrated that velocity can be modulated to some extent by external incentives. However, the ability to voluntarily control saccadic velocity and its association with motivation has yet to be investigated. Here, in three separate experimental paradigms, we measured the effects of incentivisation on saccadic velocity, reaction time and preparatory pupillary changes in 53 young healthy participants. In addition, the ability to voluntarily modulate saccadic velocity with and without incentivisation was assessed. Participants varied in their ability to increase and decrease the velocity of their saccades when instructed to do so. This effect correlated with motivation level across participants, and was further modulated by addition of monetary reward and avoidance of loss. The findings show that a degree of voluntary control of saccadic velocity is possible in some individuals, and that the ability to modulate peak velocity is associated with intrinsic levels of motivation.

Effort-based decision making is a cognitive process crucial to normal motivated behaviour. Apathy is a common and disabling complication of Parkinson’s disease, but its aetiology remains unclear. Intriguingly, the neural substrates associated with apathy also sub-serve effort-based decision making in animal models and humans. Furthermore, the dopaminergic system plays a core role in motivating effortful behaviour for reward, and its dysfunction has been proposed to play a crucial role in the aetiology of apathy in Parkinson’s disease. We hypothesised that disrupted effort-based decision making underlies the syndrome of apathy in Parkinson’s disease, and that this disruption may be modulated by the dopaminergic system. An effort-based decision making task was administered to 39 patients with Parkinson’s disease, with and without clinical apathy, ON and OFF their normal dopaminergic medications across two separate sessions, as well as 32 healthy age- and gender-matched controls. On a trial-by-trial basis participants decided whether to accept or reject offers of monetary reward in return for exerting different levels of physical effort via handheld, individually calibrated dynamometers. Effort and reward were manipulated independently, such that offers spanned the full range of effort/reward combinations. Apathy was assessed using the Lille apathy rating scale. Motor effects of the dopamine manipulation were assessed using the UPDRS part three motor score. The primary outcome variable was choice (accept/decline offer). analysed using a hierarchical generalised linear mixed effects model, and the vigour of squeeze (Newtons exerted above required force). Both apathy and dopamine depletion were associated with reduced acceptance of offers. However, these effects were driven by dissociable patterns of responding. While apathy was characterised by increased rejection of predominantly low reward offers, dopamine increased responding to high effort, high reward offers, irrespective of underlying motivational state. Dopamine also exerted a main effect on motor vigour, increasing force production independently of reward offered, while apathy did not affect this measure. The findings demonstrate that disrupted effort based decision making underlies Parkinson’s disease apathy, but in a manner distinct to that caused by dopamine depletion. Apathy is associated with reduced incentivisation by the rewarding outcomes of actions. In contrast, dopamine has a general effect in motivating behaviour for high effort, high reward options without altering the response pattern that characterises the apathetic state. Thus the motivational deficit observed in Parkinson’s disease appears not to be simply secondary to dopaminergic depletion of mesocorticolimbic pathways, suggesting non-dopaminergic therapeutic strategies for apathy may be important future targets.

The study aimed to assess dyslipidemia pattern including role of non HDL cholesterol (non HDLc) in ischemic strokes. A retrospec-tive descriptive was conducted on 80 patients who were admitted to Osmania General Hospital between May 2013 and May 2015 with new onset of stroke. A detailed history, physical examination and outcome details were collected from the hospital medical rec-ords. Data such as fasting lipid profile was noted, non HDLc was calculated, computed tomography (CT) or magnetic resonance imaging (MRI) brain reports were collected from medical records. Among enrolled patients, 55 were males and 25 were females. Age distribution: 60 years, n=26. Dyslipidemia as per ATP III guidelines was present in 92.5% cases (n = 74). In our study, high LDL was found in 16 cases (21.62%), high total cholesterol in 16 cases (21.6%), low HDL in 57 cases (77%), high triglycerides in 13 cases (17.56%) and elevated non HDLc (>130mg/dl) in 28 patients (37.8%). Risk factors for stroke present were hypertension (n=48, 60%), diabe-tes (n=18, 22.5%), both diabetes and hypertension (n=15, 18.75%), smoking (n=33, 41.25%), alcoholism (n=32, 40%) and more than 2 risk factors were present in 28.75% (n=23). Total number of deaths was 05%. To conclude, most of the patients were having low HDL (

SummarySpeed-accuracy trade-off is an intensively studied law governing almost all behavioral tasks across species. Here we show that motivation by reward breaks this law, by simultaneously invigorating movement and improving response precision. We devised a model to explain this paradoxical effect of reward by considering a new factor: the cost of control. Exerting control to improve response precision might itself come at a cost—a cost to attenuate a proportion of intrinsic neural noise. Applying a noise-reduction cost to optimal motor control predicted that reward can increase both velocity and accuracy. Similarly, application to decision-making predicted that reward reduces reaction times and errors in cognitive control. We used a novel saccadic distraction task to quantify the speed and accuracy of both movements and decisions under varying reward. Both faster speeds and smaller errors were observed with higher incentives, with the results best fitted by a model including a precision cost. Recent theories consider dopamine to be a key neuromodulator in mediating motivational effects of reward. We therefore examined how Parkinson’s disease (PD), a condition associated with dopamine depletion, alters the effects of reward. Individuals with PD showed reduced reward sensitivity in their speed and accuracy, consistent in our model with higher noise-control costs. Including a cost of control over noise explains how reward may allow apparent performance limits to be surpassed. On this view, the pattern of reduced reward sensitivity in PD patients can specifically be accounted for by a higher cost for controlling noise.

Precision irrigation system is basically based on a detailed monitoring of information and data that are necessary for successful decision making in farm production. Wireless Sensor Networks (WSNs) are used for collecting, storing and sharing sensed data. WSN have attracted much attention of researchers in recent years. In past years an extensive research and development work has been done in the field of WSN in the world. WSN have been used for various applications including agriculture, nuclear reactor control, habitat monitoring, environmental monitoring, security and tactical surveillance. WSN have immense potential such that if properly designed and developed can be a solution to a low cost precision irrigation system. The WSN system developed in this paper is for use in precision irrigation system, where real time data of environment and climate are sensed and according to the sensed data a control decisions are taken so that we can modify them. The architecture of WSN consist of a sensor node placed in a field which sends the sensed data to the base station so that a global decision can be taken about the physical environment. This irrigation system promises to give a higher yield and lower input cost by real time monitoring of the field soil and environment conditions using different sensors and thereby improving crop cultivation, reducing time and labor costs.

Objective The identification of new uncultured species and viruses supports the possibility of combination of the herpesvirus- bacterial periodontal infection for periodontitis. The paucity of data and studies with larger sample size in Indian subjects provides an unclear picture of the presence of the herpesvirus in this population. Materials and methods This was a cross-sectional study consisting of 100 each in the healthy group and chronic periodontitis (CP) group. The subgingival plaque was collected and polymerase chain reaction was performed post deoxyribonucleic acid (DNA) extraction by using specific primers for human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV). The data were analyzed using Fisher's exact test, Mann-Whitney U test and Spearman's coefficient correlation. Results Human cytomegalovirus and EBV viruses were significantly higher in the CP group as compare to the healthy group. A higher percentage of those with CMV positive had EBV also positive (28.3%) compared to only 9.1% of CMV negative being EBV positive in the CP group. When both the healthy and CP group in total was compared, there was a significant correlation with all clinical parameters. Conclusion Both the viruses dominated in disease as compared to health were similar to the earlier findings. The CP group had higher pocket depth and clinical attachment loss in the virus positive subjects. These findings could suggest that virus serves as a prelude to the disease and the combination of the two viruses could play a role in the pathogenesis. How to cite this article Joshi VM, Bhat KG, Katti SS, Kugaji MS, Ingalgi PS. Prevalence of Herpesvirus and Correlation with Clinical Parameters in Indian Subjects with Chronic Periodontitis. J Contemp Dent Pract 2015;16(11):915-920.

Different applications have come out as in the field of Wireless Sensor Network (WSN) by years of research. At present, Lossy Networks (LLNs) are in the center of area of studies. LLNs are made up of Wireless Personal LANs, low-power Line Communication Networks, and Wireless Sensor Networks. In such LLNs, for sending protected data, routing IPv6 routing protocol is used for minimum-power as well as not reliable networks (RPL) controlled by Internet Engineering Task Force (IETF) routing protocol. A route created by rank-based RPL protocol for the sink based in the rank value and link quality of its neighbors. But, it has few site backs for example, high packet loss rates, maximized latency, and very low security. Packet losses as well as latency get maximized as the length of path (in hops) increases as with every hope a wrong parent link is chosen. For increasing the RPL system and to solving issue stated above, a Trust Management System is proposed. Every node is having a trust value. Trust value will increase or decrease depending to behavior of node and trusted path is selected for delivering the data. For increasing energy efficiency, at the time of data transferring “compress then send” method is used, this results in minimum utilization of energy reduced data size. By making use of cryptography, we gained data security which is the key concern. By analyzing the test outcomes conducted on JUNG simulator shows, our proposed system have increased the packet delivery ratio by having trust management system while transferring the data, increases energy efficiency by utilizing the data compression, network security is improved by utilizing encryption decryption method as compared to present system.

Deficits in working memory (WM) in Parkinson’s disease (PD) are often considered to be secondary to dopaminergic depletion. However, the neurocognitive mechanisms by which dopamine causes these deficits remain highly contested, and PD is now also known to be associated with nondopaminergic pathology. Here, we examined how PD and dopaminergic medication modulate three components of WM: maintenance over time, updating contents with new information and making memories distracter-resistant. Compared with controls, patients were disproportionately impaired when retaining information for longer durations. By applying a probabilistic model, we were able to reveal that the source of this error was selectively due to precision of memory representations degrading over time. By contrast, replenishing dopamine levels in PD improved executive control over both the ability to ignore and update, but did not affect maintenance of information across time. This was due to a decrease in guess responses, consistent with the view that dopamine serves to prevent WM representations being corrupted by irrelevant information, but has no impact on information decay. Cumulatively, these results reveal a dissociation in the neural mechanisms underlying poor WM: whereas dopamine reduces interference, nondopaminergic systems in PD appear to modulate processes that prevent information decaying more quickly over time.

The wireless sensor network (WSN) is one of the resource constrained ad-hoc communication networks, having limited resources such as storage space, energy and computational capability. In addition to this it suffers from quick changes in the structure of the wireless link due to variations of the signal strength, interference, and multi-path propagation characteristics. Reliable energy efficient data transmission in WSNs to prolong the network lifetime is an important and challenging issue. In general, there are several approaches like multi-path routing and source coding, automatic repeat request, used for providing reliable data transfer in WSNs. But the overhead and performance of such end-to-end single-path approaches are often dominated by congestion as well as some poor-quality links or nodes on the path. That is, these traditional approaches are not able to quickly and properly react in this multi-hop wireless environment. To cope with the above issues, in this paper we propose an energy efficient reliable data transfer scheme named as "Adaptive Sectoring Scheme for Reliability (ASSR)" for WSNs. In this approach, the given sensor field is divided into sectors activated one at a time by the occurrence of an event. To minimize the congestion as well as to increase the throughput with maximum packet delivery ratio, the sectoring process is adjusted dynamically to ensure reliable data transmission. Simulation experiments show that the proposed scheme leads to an improvement of the reliability and energy consumption.

Two phosphorescent cyclometalated iridium(III)-triptycenyl-1,10-phenanthroline complexes [Ir(ppy)2(tpt-phen)]+ (1) and [Ir(bhq)2(tpt-phen)]+ (2) {ppy=2-phenylpyridine, bhq=Benzo[h]quinoline, tpt-phen=triptycenyl-1,10-phenanthroline} have been synthesized and structurally characterized. The structure of complex 2 has been studied by single crystal X-ray crystallography. The photophysical properties of complexes in a different solvent have also been investigated. The binding of complexes to the double stranded calf thymus (CT-DNA) has been investigated by spectroscopic techniques. These complexes condense originally circular plasmid DNA into particulate structures. The DNA-condensation induced by these complexes have been investigated by electrophoretic mobilty shift assay, dynamic light scattering, and fluorescence microscopy. Furthermore, the cytotoxicity of these complexes towards HeLa cells have been studied and their cellular localisation properties have been investigated by fluorescence microscopy.

A mobile ad hoc network (MANET) is dynamic, ad hoc, infrastructure less and self-configurable having autonomous nodes. Route discovery in MANET is dynamic. Security from malicious attacks in MANET is a huge challenge. Topology hiding is a technique to improve MANET security. Topology Hiding hides topology information sent from a network to an untrusted Network. It also restores the topology. One such protocol Topology-Hiding Multipath Routing protocol (THMR) overcomes the threat of topology-exposure. Our proposed Modified THMR (M-THMR) improves upon THMR and works on fault nodes detection and avoidance. The protocol is implemented for performance comparison with THMR protocol. Experimental results show that M-THMR protocol is well performs better in delay, packet delivery and packet loss with low overhead.

Highlights • Analog report methods provide novel insights on STM for space and time. • Space and time may be used to bind features in STM. • The hippocampus is involved in object-location binding in STM., Space and time appear to play key roles in the way that information is organized in short-term memory (STM). Some argue that they are crucial contexts within which other stored features are embedded, allowing binding of information that belongs together within STM. Here we review recent behavioral, neurophysiological and imaging studies that have sought to investigate the nature of spatial, sequential and duration representations in STM, and how these might break down in disease. Findings from these studies point to an important role of the hippocampus and other medial temporal lobe structures in aspects of STM, challenging conventional accounts of involvement of these regions in only long-term memory.

This scientific commentary refers to ‘Selective impairment of goal-directed decision-making following lesions to the human ventromedial prefrontal cortex’, by Reber et al. 2017 (doi:10.1093/brain/awx105).

When rewards are available, people expend more energy, increasing their motivational vigor. In theory, incentives might drive behavior for two distinct reasons: First, they increase expected reward; second, they increase the difference in subjective value between successful and unsuccessful performance, which increases contingency—the degree to which action determines outcome. Previous studies of motivational vigor have never compared these directly. Here, we indexed motivational vigor by measuring the speed of eye movements toward a target after participants heard a cue indicating how outcomes would be determined. Eye movements were faster when the cue indicated that monetary rewards would be contingent on performance than when the cue indicated that rewards would be random. But even when the cue indicated that a reward was guaranteed regardless of speed, movement was still faster than when no reward was available. Motivation by contingent and certain rewards was uncorrelated across individuals, which suggests that there are two separable, independent components of motivation. Contingent motivation generated autonomic arousal, and unlike noncontingent motivation, was effective with penalties as well as rewards.

When rewards are on offer, we put more energy in, increasing “motivational vigour”. In theory, incentives might drive behaviour for two distinct reasons: first, they increase expected reward; second, they increase the value difference between successful and unsuccessful performance, increasing contingency. Previous studies of motivational vigour never compared these directly. To index vigour, we measured the speed of eye movements towards targets, after participants heard a cue indicating how outcomes would be determined. After cues indicating that monetary reward would be contingent on performance, movements were faster than if reward was random. But even when the cue indicated that reward was guaranteed regardless of speed, movement was still faster than when no reward was available. Contingent motivation generated autonomic arousal, and unlike non-contingent motivation, was effective with penalties as well as rewards. Crucially, motivation by contingent and certain rewards was uncorrelated across individuals, suggesting two separable, independent components of motivation.

Capacity limitations in working memory (WM) necessitate the need to effectively control its contents. Here, we examined the effect of cabergoline, a dopamine D2 receptor agonist, on WM using a continuous report paradigm that allowed us to assess the fidelity with which items are stored. We assessed recall performance under three different gating conditions: remembering only one item, being cued to remember one target among distractors, and having to remember all items. Cabergoline had differential effects on recall performance according to whether distractors had to be ignored and whether mnemonic resources could be deployed exclusively to the target. Compared with placebo, cabergoline improved mnemonic performance when there were no distractors but significantly reduced performance when distractors were presented in a precue condition. No significant difference in performance was observed under cabergoline when all items had to be remembered. By applying a stochastic model of response selection, we established that the causes of drug-induced changes in performance were due to changes in the precision with which items were stored in WM. However, there was no change in the extent to which distractors were mistaken for targets. Thus, D2 agonism causes changes in the fidelity of mnemonic representations without altering interference between memoranda.

Introduction: Periodontitis is a chronic destructive inflammatory disease of the oral cavity. The main causative agent is presence of biofilm formed due to different micro-organisms. Among different micro- organisms “red complex” bacteria is known to be the main causative agent in progression of periodontitis. Porphyromonas gingivalis out of the red the complex organism plays a major role in progression of periodontitis. P. gingivalisis present in both in healthy and diseased individuals. The difference in the strains will determine the virulence factor of the organism and also progression of disease. Only few studies have been done showing variation in strains present between healthy and diseased. Aims: To check the difference in heterogeneity of P. gingivalis in chronic periodontitis and healthy individuals through Arbitrarily Primed-PCR (AP-PCR). Materials and Methods: A total of 400 subjects (200 each of chronic periodontitisandhealthy individuals) were included. Sub-gingival plaque was collected in the Reduced transport fluid (RTF) medium and processed at the institutional central research laboratory. Presence of P. gingivalis was, confirmed by culture andphenotypical analysis. Further confirmed cases were processed for PCR after DNA extraction using 16S rRNA. Positive cases of P. gingivalis were subjected for AP-PCR for clonal analysis using the specific 272 primer. Results: In 152(76%) and 98(49%) were confirmed for P. gingivalis in chronic periodontitis and healthy individual respectively by PCR. AP-PCR analysis showed 6 clusters with similarity index in CP and 3 clusters with similarity index in Healthy individuals. Conclusion: The present study showed difference in clusters between chronic periodontitis and healthy individual'sthussuggestive variantin genetic heterogeneity of P. gingivalis strain between healthy and chronic periodontitis. AP- PCR appears to be a promising tool for clonal analysis of P. gingivalis.

Introduction: Capnocytophaga species are recognized as part of human oral microbiota and implicated as periodontal pathogens associated with various periodontal diseases. The three original Capnocytophaga species - Capnocytophaga ochracea, Capnocytophaga sputigena and Capnocytophaga gingivalis were initially isolated from periodontitis in adults, but subsequent studies demonstrated their presence also at periodontally healthy sites in both children and adults. Their association with periodontal disease is a matter of controversy. Considering the differing virulence features of the respective isolate, it is crucial to identify these isolates to species level. Aims: The aim of this study is to investigate the prevalence of Capnocytophaga species by polymerase chain reaction (PCR) through restriction fragment length polymorphism in healthy individuals and patients with periodontal disease. Material and Methods: The study included a total of 300 individuals, 100 each with Gingivitis, Chronic periodontitis, and Healthy individuals. The plaque samples were collected using sterile curette in reduced transport fluid. DNA extraction was carried out for PCR analysis. Results: Of 300 individuals, Capnocytophaga species were identified from 237 (79%) participants in all groups. The prevalence was statistically analyzed using Chi-square test. The prevalence was more in males in gingivitis and healthy individuals (42% and 49% respectively), and females in periodontitis (40%). C. ochracea was observed in a higher proportion (36.33%), followed by C. granulosa (32.66%) and C. gingivalis (10%). They were identified more in the age group of 30–40 years in gingivitis and periodontitis, (30 and 21 individuals, respectively) and 39 individuals in 18–29 years in healthy individuals. They were present in 87% in healthy individuals, 77% in gingivitis and 73% in periodontitis. Conclusion: Capnocytophaga species are commonly present in healthy individuals and may be associated with periodontal disease. There is a need for further study to know the prevalence of other species of Capnocytophaga in health and disease.